Animal litter, process for preparing animal litter and method of removal of animal waste

ABSTRACT

An animal litter, process for preparing the animal litter and a method for removal of animal waste using the animal litter are provided. The animal litter generally includes corn cob, a lubricant, and a cohesiveness agent. The animal litter is in the form of discrete plural particles which tend to agglomerate when wetted.

RELATED APPLICATION

This application claims the benefit of prior provisional applicationSer. No. 61/600,971. The entire contents of the foregoing provisionalapplication are hereby incorporated by reference in their entireties.Also incorporated in their entireties are the disclosures of priorprovisional application Ser. Nos. 61/600,966; 61/600,976; and61/600,978.

FIELD

The present application relates to an animal litter, and moreparticularly to a litter that includes ground corn cob. The applicationfurther pertains to a process for preparing an animal litter, methodsfor removal of animal waste, and related products, processes, andmethods.

BACKGROUND

Clumping animal litters are typically provided in the form of discreteplural particles. The particles tend to agglomerate into solid masses orclumps when wetted by a liquid waste such as animal urine. A number ofsuch clumping litters are known. One advantage of such clumping littersis that the solid clumps, which are formed upon wetting of the litter,can be separately removed as discrete entities from the remaininglitter. The clumped litter can be discarded by the animal owner, leavingbehind a quantity of relatively uncontaminated litter for future use.Animal owners, particularly owners of house cats, often find theclumping property of such litters to be convenient for periodic cleaningof the animal litter box. Ammonia-masking properties also are desirablein animal litters because ammonia, a breakdown product of the urea foundin animal urine, is a significant factor that contributes to theundesirable odor of animal waste. Some known animal litters have goodammonia-masking properties.

Many clumping animal litters are made from clays and other mineralsubstrates. Such litters typically include particles of a mineralsubstrate, which substrate functions as an absorbent and/or odorreducer. The particles may be coated with a liquid-activated adhesivematerial, such as gelatinized starch, on the surfaces of the particles.When wetted, the adhesive material is activated and causes the discretelitter particles to agglomerate into clumps.

Although clay-based litters may be functional as clumping animallitters, such litters may have different features and characteristicscompared to other materials. For example, one feature of clay litters isthe high density of the clay component of the litter. Because of thishigh density, a relatively heavy mass of litter must be used for a givenvolume of urine. In addition, the resulting clumps of soiled litter aresomewhat heavy, and thus can fracture in the absence of strong particleadhesion. Another feature of clay litters is that, because the clay isnot biodegradable, the litter cannot be flushed into some sewage systemsafter use. This may be inconvenient for certain animal owners.

In recognition of these features, animal litters made from biodegradablematerials, such as seed hulls or other grain-based materials, have beenprovided. Such litters are often suitable for disposal by flushing intosewage systems. For instance, U.S. Pat. No. 6,014,947 purports todisclose a grain-based litter made from whole wheat or other groundgrains. In recognition of the features inherent in clumping animallitters, biodegradable litters that exhibit a clumping property haveundergone development. Like typical clumping clay litters, such littersoften comprise discrete particles of a liquid-absorbent substrate havinga liquid-activated adhesive coated thereon.

Numerous litters are disclosed in U.S. Pat. Nos. 7,757,638; 7,753,002;6,868,802; 6,622,658; 6,405,677; 6,216,634; and 6,098,569, as well asU.S. application Ser. No. 13/103,778, all assigned to Grain ProcessingCorporation of Muscatine, Iowa. These patents provide excellentteachings as to organic, biodegradable litters that, in preferredembodiments, are based exclusively on natural materials. The littersdisclosed in these patents have excellent ammonia absorbing properties.

The present application seeks to provide an animal litter that differsfrom the heretofore described litters.

SUMMARY

An animal litter, process for preparing the animal litter and a methodfor removal of animal waste using the animal litter are provided. Theanimal litter generally includes corn cob and other ingredients.

In many embodiments, no more than about 5% of the corn cob particlesused to prepare the litter are larger than U.S. standard #30 mesh screensize while at least 50% of the corn cob particles are smaller than U.S.standard #40 mesh screen size and at least 20% of the particles aresmaller than U.S. standard #80 mesh screen size.

In many embodiments, not mutually exclusive with respect to theheretofore described embodiments, the litter includes at least about 35weight corn cob, a lubricant, and a cohesiveness agent. The animallitter is in the form of discrete plural particles which tend toagglomerate when wetted.

Further, in some embodiments a process for preparing an animal litter isalso provided. The process includes the steps of providing a mixture ofat least a first sorbent comprising ground corn, a lubricant, and acohesiveness agent; and compacting the mixture of into discrete pluralcompacted particles which tend to agglomerate when wetted. The groundcorn may be present in an amount of at least 35% and may have theparticle size distribution heretofore described. The litter may includeadditional sorbents, such as wood fibers, malt sprouts, or corn germ.

Additionally, a method for removal of animal waste is provided in someembodiments. The method includes the steps of providing a container thatincludes an animal litter, allowing an animal to excrete waste into saidlitter, whereby liquid present in said container as a result of saidwaste causes at least a portion of said litter to agglomerate into atleast one clump, and removing the clump from the container. The animallitter includes a first sorbent that comprises ground corn, in manycases at least about 35% ground corn, a lubricant, and a starchcohesiveness agent. The corn may have the particle size distributionheretofore described. The animal litter is in the form of discreteplural compacted particles which tend to agglomerate when wetted.Further, the cohesiveness agent is present in said litter in an amounteffective to enhance the intraparticle cohesion of said particles.

These and other aspects may be understood more readily from thefollowing description.

DETAILED DESCRIPTION

The animal litters described herein may be formulated as dumping littersor as non-clumping litters but generally is provided in the form of adumping litter. The litter preferably is formulated to take the form ofpellets or other compacted forms, particularly when the litter isintended as a cat litter.

After the litter has become soiled, the liquid in the animal urine willcause some of the litter to form a dump. The soiled litter then may beremoved from the box by removing the clump and any solid waste litterfrom remaining unsoiled litter and disposing of the soiled litter.Alternatively, the soiled litter may be removed without separating itfrom any unsoiled litter in the box, by disposing of all orsubstantially all of the litter in the box. In either case, animal wastewill be thereby removed. Optionally, the supply of litter may bereplenished with fresh litter.

A range of desired properties for clumping animal litter has beenidentified. These properties include biodegradability, high sorptioncapacity, cohesion, clumpablility, ammonia and other odor masking, adensity and texture that is acceptable for the target animal, clumpstrength, tendency to remain clumped, clump weight, and cost. Ingeneral, the various ingredients and processing conditions may beselected to accommodate a desired combination of properties. Somecombinations of ingredients and processing conditions may not yield alitter that is commercially satisfactory. Selection of appropriateingredients and processing conditions will become apparent upon reviewof the following description.

In one embodiment, the animal litter is in the form of discrete pluralparticles, which particles generally are sufficiently cohesive for useas an animal litter. By “particles” it is contemplated granules orpellets obtained by compaction. The compaction may be any processsuitable for compressing the ingredients from which the litter iscomposed to an extent that the internal cohesion of the ingredients isincreased. Generally, the mass of ingredients should become sufficientlyinternally cohesive for use as an animal litter. The preferred method ofcompaction is by pelletizing the mixtures of ingredients in a pelletmill, but other processes (such as extrusion) may be employed.Generally, the pellets formed in a pellet mill (or the extrudate formedupon extruding the litter components) should be subjected to a processsuch as crumbling, to reduce the size of the pellets (or extrudate).

The animal litter generally includes ground corn cob in combination withother materials. Corn cob is believed to function as a sorbent foranimal urine, and to contribute favorably to the clumping properties ofthe litter. To enable clumping, the ground corn cob should be providesas a finely ground material. In this regard, the corn cob material maybe finely ground such that it passes through a 1/16 inch screen, such asfound in a hammer mill. Other forms and particle sizes of corn cobmaterial may also be included in the animal litter. For example, corncob material may be ground to have a larger and/or smaller particle sizeand may also be included in a combination of particle sizes. In manyembodiments, no more than about 5% of the corn cob particles used toprepare the litter are larger than U.S. standard #30 mesh screen sizewhile at least 50% of the corn cob particles are smaller than U.S.standard #40 mesh screen size and at least 20% of the particles aresmaller than U.S. standard #80 mesh screen size. Although it is notintended to limit the invention to a particular theory of operation, itis believed that the particle size distribution heretofore describedwill yield particles with sufficiently small surface area to enhanceabsorption of liquid relative to particles of larger surface area whilestill allowing for ready processing in the manner discussed herein.

In some embodiments, the ground corn cob has the following screenprofile:

% over % over % over % over % over % over % Thru #8 #14 #20 #30 #40 #80#80 Total 0.3 0.5 0.6 12.1 21.6 33.4 31 99.5

The corn cob material may be included in the litter in range of amounts.For example, in one form, the corn cob material is included such that itforms at least about 35% of the overall animal litter composition. Thecorn cob material may also be included in larger amounts, such as about65% of the animal litter composition. In one form, the corn cob materialis included in an amount of about 30% to about 85%.

The animal litter may include one or more lubricants including fats,oils and mixtures thereof. The lubricant is not necessarily believed toprovide desired properties itself to the litter, but is believed to beuseful in connection with the preparation of the litter. The lubricantcan be present in any amount sufficient to facilitate the compaction ofthe animal litter composition into particles, as described herein. Forexample, in one form, the animal litter includes ground virgin corngerm. Virgin germ contains oils and used as a lubricant. The germ may beincluded in any suitable amount. A typical range of amounts will be fromabout 1% to about 10% by weight.

Other suitable lubricants include, for example, fats and oils. Exemplaryfats include lauric fats, such as babassu, coconut and palm kernel, andanimal fats, such as butter oil, chicken fat, lard and beef tallow.Exemplary oils include fish oils, such as menhaden, and vegetable oils.Preferred vegetable oils include, for example, canola, cocoa butter,corn, cottonseed, olive, palm, peanut, rapeseed, soybean and sesame.Preferably, the lubricant is a vegetable oil because animals are oftenattracted to animal fats and fish oils as a food source. When used, suchlubricant may be effect, may be used in any suitable amount, such as1-10% by the weight.

The animal litter also includes at least one cohesiveness agent which isemployed to effect intraparticle cohesion. Prior art litters employmodified, pre-gelatinized starches to effect adhesion between particlesof litter, i.e., interparticle adhesion. When a polysaccharidecohesiveness agent is employed, the cohesiveness agent is believed toprovide additional hydroxyl groups, which enhance the bonding betweengrain proteins within the litter granule. It is further believed thatthe additional hydroxyl groups so function by enhancing the hydrogenbonding of proteins to starch and to other proteins. The cohesivenessagent may be present in any amount suitable to enhance the cohesivenessof the granules of animal litter.

The cohesiveness agent preferably is a polysaccharide. Any suitablepolysaccharide may be used in conjunction with the invention and thus,for example, the cohesiveness agent may comprise one or morepolysaccharides such as dextrins, maltodextrins, starches, flours,cellulosics, hemicellulosics, and the like. Preferably, the cohesivenessagent comprises a starch, and most preferably, the cohesiveness agentcomprises a corn starch. It has been found that non-gelatinized,unmodified starches are especially suitable for use as cohesivenessagents in conjunction with the invention. When unmodified starches areemployed, it is believed that such starches may contribute to a smallextent to interparticle adhesion in the clumped litter.

The cohesiveness agent may further include a fibrous material. Fibersfor use as a cohesiveness agent include soluble and insoluble fiberssuch as apple fiber barley-bran flour, barley-flour, brewers spentgrain, carrageenan gum, citrus fiber, citrus pulp sacs, cocoa, cornbran, corn fiber, dried cranberries, fig powder, guar gum, gum agar, gumArabic, locust bean gum, oat bran, oat fiber, pea fiber, powderedcellulose, dried prunes, defatted rice bran, stabilized rice bran, ricefiber, sodium carboxymethylcellulose, soy fiber, sugar beat fiber, wheatbran, and detailed wheat germ. Other suitable fibers include, forexample, cellulose, microcrystalline cellulose, resistant starch,chitin/chitosan methylcellulose, hydroxypropyl methylcellulose,carboxymethylcellulose, pectin, alginate, karaya tragacanth, gellan,arabinogalactan, inulin, konjac flour, psyllium seed husk, curdlan, andpolydextrose. It is contemplated that some of these materials willfunction as sorbents in some embodiments. To the extent that acohesiveness agent is indeed in the litter formation, the cohesivenessagent is an ingredient that is different from the “sorbent.” in otherwords a litter that is said to include both a “sorbent” and a“cohesiveness agent” will have separate ingredients for the sorbent andthe cohesiveness agent, even though the cohesiveness agent may have itsown sorption properties and even thought the sorbent may contain plantfiber.

The cohesiveness agent may be included in a variety of amounts. Forexample, in one form, the cohesiveness agent is included in a range ofabout 5% to about 40%. Other cohesiveness agents and amounts ofcohesiveness agents may be included as discussed in more detail below.The litter may include further includes a supplemental cohesivenessagent, which is an ionic species that is believed to enhanceprotein-protein and/or protein-starch interactions. Any suitable ionicsalt may be used in conjunction with the invention. For example, thesupplemental cohesiveness agent may be selected from among the alkaliand alkaline-earth salts of common anions, such as the halide, nitrate,nitrite, carbonate, phosphate, sulfate, and bicarbonate salts, and thelike. Exemplary supplemental cohesiveness agents include of sodiumchloride, calcium chloride, sodium carbonate, calcium carbonate, sodiumbicarbonate and mixtures thereof. The supplemental cohesiveness agentmay be present in any amount sufficient to assist the cohesiveness agentin enhancing the cohesion of the animal litter granules.

Further, the animal litters may include ingredients such as whole groundgrain, or grain meal. By “plant meal” it is meant to include meals orflours from grain, beans, grass, and the like, which are typicallythought of as agriculturally derived meals or flours. Any plant mealthat may be formulated into a clumping litter in accordance with theteachings herein may be deemed suitable for use. The plant mealpreferably is a grain meal, i.e., a ground grain, and preferably is aground whole grain. In some embodiments, ground fines can be removedfrom a whole grain meal, such as by screening. The remaining groundproduct is still deemed to be a whole grain meal within the meaning ofthe present application. Suitable plant meals include, for example, cornmeal, soy meal, sorghum meal, alfalfa meal, barley meal, and the like.Combinations of two or more of the foregoing may be used. Preferably,the grain meal used in the animal litter includes a grain meal derivedfrom an oil-rich grain. Most preferably, the grain meal is derived fromcorn grain.

For practical considerations, the grain meal preferably consists of awhole unprocessed grain meal, though a processed grain meal or acombination of a whole grain meal and a processed grain meal may also beused in the animal litter. By “whole grain meal” it is meant to includea milled whole grain, such as grain meal that is produced in a wet ordry milling process. Processed grain meal includes, for example, meal orflour from which the germ or bran has been removed. In one preferredembodiment, the grain meal used in the animal litter includes whole cornmeal or a combination of whole corn meal and processed corn meal, suchas defatted corn meal obtained from a solvent extraction or pressextraction process.

In some embodiments, the litter includes a plant fiber that is effectivein enhancing the agglomeration of the particles of litter when wetted.In one form, the fiber is present in at least an amount effective toenhance the agglomeration of the particles of animal litter when theparticles are contacted with a liquid such as animal urine. Withoutbeing bound by any particular theory, it is contemplated that the fiberprovides for an enhancement of clump strength, or an increase in dumpcohesiveness, and in many embodiments, an increase in both clumpstrength and cohesiveness. The enhancement in particle agglomeration,with respect both to clump strength and cohesiveness, is believed to bedue to enhancement of adhesion between the particles, which in somecases is believed to be due to hydrogen bonding phenomena. Clumpstrength is a measure of the force required to fracture a clump ofanimal litter, while cohesiveness is a measure of the friability of aclump. A high clump strength is advantageous in that it reduces thelikelihood of breakage of the clumps, thereby allowing the soiled animallitter to be removed more effectively. High clump strength alsominimizes the likelihood of leaving behind soiled animal litter that maybreak off upon removal of soiled clumps. Both clump strength andcohesiveness, but especially cohesiveness, may be qualitativelyevaluated with the increase in these properties being evaluated relativeto an animal litter that does not include the fiber.

Any suitable plant fiber or combination of fibers may be used. Exemplaryplant fibers include grain bran and citrus residues. Preferred grainbrans include, for example, wheat bran, corn bran, soy bran, sorghumbran, barley bran, or any combination thereof. Preferably, the grainbran includes a ground corn bran. In one form, the grain bran ispreferably present in an amount of from about 1% to about 90%, morepreferably from about 3% to about 70%, even more preferably from about4% to about 50%, and most preferably from about 5% to about 30% byweight of the animal litter. These amounts are exclusive of any branpresent in the grain meal, with the proviso that the invention is notintended to encompass ground whole grain to which nothing has beenadded. If the litter is embodied in a product that comprises one or bothof grain meal or grain germ in combination with a grain bran, the grainbran being a bran from the same grain from which the meal is derived,then in preferred embodiments the bran is present in the litter in anamount greater than that in which the bran would naturally be present inground whole grain. Preferably, the bran is present in an amount of atleast 5% more than would be present in the ground whole grain; morepreferably, the bran is present in an amount of at least 10% more thanwould be so present. In some embodiments, a litter may comprise one orboth of a grain meal or grain germ in combination with a grain bran, thegrain bran being a bran from a different grain than the grain from whichthe meal or germ is derived. More generally, the germ, grain, andcohesiveness agent should be present as discrete ingredients, by whichis contemplated that the various components of the litter do notcomprise a whole ground grain, or constitute ingredients which whencombined and ground are indistinguishable from whole ground grain(although whole ground grain may be a component of the animal litter).

The plant fiber used can include a combination of fibers. In oneembodiment, the combination of fibers includes a combination of grainbran and citrus fiber. In this embodiment, the fiber can include amixture of a grain bran, citrus peels and citrus pulp. When the fiberincludes grain bran and a citrus peel/pulp combination, it is preferredthat the grain bran is present in an amount of from about 10% to about20% by weight of the litter, and the combination of citrus peel andcitrus pulp is present in an amount of from about 10% to about 20% byweight of the animal litter.

Because the animal litter is made from biodegradable materials, thelitter is subject to spoilage, such as by molding or bacterial action.To prevent or inhibit such spoilage, the litter can include a microbialinhibitor. A microbial inhibitor can be present in any amount effectiveto inhibit or prevent the spoilage of the animal litter. Typically, anyingredient capable of maintaining a pH of the animal litter from about 3to about 55 is effective to prevent or inhibit spoilage of the animallitter.

In one embodiment, the spoilage inhibitor is a mold inhibitor. Anysuitable mold inhibitor can be employed in conjunction with theinvention. The mold inhibitor can include, for example, sodium chloride(which can also provide supplemental cohesive properties), propionicacid, propionate salts (e.g., sodium propionate, calcium propionate andthe like), citric acid, citric acid salts (e.g., sodium citrate, calciumcitrate, potassium citrate and the like), benzoate salts (e.g., sodiumbenzoate), parabens (e.g., methylparaben, ethylparaben, propylparabenand the like), sorbic acid, and sorbic acid salts (e.g., potassiumsorbate and the like), lactic acid and lactic acid salts, acetic acidand acetic acid salts, alginic acid and alginic acid salts, and anycombination thereof.

Preferably, the mold inhibitor includes citric acid, sodium chloride,potassium sorbate, or any combination thereof. More preferably, the moldinhibitor includes a combination of citric acid, sodium chloride andpotassium sorbate or a combination of citric acid and sodium chloride.When citric acid is used, it is preferably present in an amount of about0.5% to 2% by weight of the animal litter. When sodium chloride is used,it is preferably present in the animal litter in an amount of about 2%by weight of the animal litter (sodium chloride is believed to functionas a supplemental cohesiveness agent when used in this amount). Whenpotassium sorbate is used, it is preferably present in the animal litterin an amount of from 0.1-0.5%, more preferably from 0.1-0.2%, by weightof the animal litter. Other microbial inhibitors may be included ifdesired, and such ingredients can be present in any amount suitable fortheir intended purpose.

The animal litter may also include other materials to help in odorabsorption and/or elimination. For example, the animal litter mayinclude an odor-absorbing effective amount, such as 2 to 5%, of acarbon-based odor-absorbing material as described in U.S. ApplicationSer. No. 61/600,966, filed Feb. 20, 2012 and entitled “Odor-AbsorbingMaterials And Processes For Their Preparation And Use.” As disclosed inthe '966 application:

It has now been found that spent carbon type products from industrialprocesses, such as from food processing or water treatment processes,can be used with a limited number of ingredients to form a low density,spent carbon based, odor-absorbing granular product. It also has beenfound that activated carbon, especially powdered activated carbon, canbe usefully employed as an odor-absorbing material in animal litterformulations with improved odor-absorbing capacity and without drawbacksassociated with heretofore reported efforts with such material. In someembodiments, this activated carbon material can take the form of spentcarbon material from an industrial process.

In some embodiments, spent carbon material is subjected to heat andmechanical work, typically using an extruder, to obtain anodor-absorbing carbon product. A method for preparing an odor-absorbingproduct thus may comprise the steps of (a) extruding a blend includingspent carbon material, a binder, and optionally additional ingredientsunder conditions sufficient to obtain a cohesive cuttable extrudate; and(c) drying the extrudate to obtain the odor-absorbing product. Theodor-absorbing product preferably is an at least partially puffedproduct to thereby provide a larger odor-absorbing surface area thanwould be obtained in other granule-forming processes.

In another of its aspects, the present invention relates to a method ofprocessing spent filtration material that comprises activated carbonand, optionally, diatomaceous earth, the method comprising (a) extrudinga blend including spent carbon material, optionally, diatomaceous earth,a binder, and optionally, additional ingredients to obtain a cohesivecuttable extrudate; and (b) drying the extrudate to obtain an at leastpartially puffed odor-absorbing product. The odor-absorbing productpreferably is an at least partially puffed (relatively porous) productso carbon particles are exposed over a larger odor-absorbing surfacearea.

The at least partially puffed odor-absorbing pellet is produced viaextrusion at high temperature. When the spent carbon material has beenrecovered from an industrial process, it is believed that the heat willdenature at least in part any unwanted organic materials and willdestroy microbiological components. The spent carbon can be extrudedwith minimal moisture addition to the extruder barrel and with a normalscrew configuration. The resulting spent carbon granular pellet exhibitsthe ability to aid in odor removal where the absence of undesirableodors is preferred.

Since the product is preferably at least partially puffed, andpreferably porous, it has a significantly larger working odor-absorbingsurface area as compared to solid granulated or agglomerated particlesof an odor-absorbing product containing powdered activated carbon. Thecarbon powder is preferably embedded in and on the surface of thepresent odor-absorbing product.

The extruded, dried and odor-absorbing product may exhibit a relativelylow density, especially in embodiments in which the product is at leastpartially puffed. The product can be made to exhibit excellent handlingduring bulk loading and while being processed/handled in various typesof equipment.

The product is deemed to find particular applicability in many fieldsincluding the field of air filtration, but is deemed particularly usefulin the field of animal litters. Advantageously, the converted productcan aid in the removal of undesirable odors in congruence with litterbases. This product is suited for in home uses where odors are typicallyeither not removed or slowly removed when using the litter base itself.Advantageously, in other embodiments the product is incorporated in airfiltration systems, such as in poultry and hog farms, to remove odors.

Other aspects of the present invention involve enhancing theodor-absorbing characteristics of an existing animal litter through theaddition of the present odor-absorbing product.

In aspects of the present invention, an animal litter comprising thepresent moisture-absorbing addition is obtained. The odor-absorbingproduct can be incorporated into the animal litter as part of theprocess of preparing the animal litter from base ingredients, ordiscrete particles of the odor-absorbing product can be physicallyblended with discrete particles of a previously prepared animal litter.When added to an existing litter, the particles of odor-absorbingproduct provide additional capacity to absorb odors and undesirablearomas.

Still another aspect concerns methods for removal of waste, such asanimal waste. A container including a litter of the invention isprovided, and an animal is allowed to excrete waste into the litter,whereby liquid present in the waste causes agglomeration of at leastsome of the litter into at least one clump. The clump is then removedfrom the container. The litter is useful in conjunction with removal ofwaste from house cats, and also in conjunction with removal of wastefrom other animals, such as other mammals (e.g. rodents) and birds. Itwill be appreciated that the animal litter can be prepared from thepresent odor-absorbing product; the odor-absorbing product can beseparately prepared and blended with discrete particles of a previouslyprepared animal litter and that blend placed in the container (such as alitter box); or the additive can be separately prepared and combined toan existing litter in a container in order.

In general, spent carbon materials contemplated herein contain spentactivated or granulated carbon. The spent carbon materials can alsocontain additional filtration material such as diatomaceous earth. Inthe latter instance, the spent carbon material contains two majorconstituents: diatomaceous earth or powdered or activated carbon, inaddition to a binder. The spent carbon material can contain about 0% toabout 80 wt. % diatomaceous earth and from about 100% to about 20 wt. %powdered or activated carbon.

The spent carbon material can be recovered from a water treatmentprocess or from a food process, as examples. Food processes includestarch hydrolysis as well as brewing. For example, the spent carbonmaterial can be recovered from a brewing process or a starch hydrolysisproduction facility and then re-purposed in a present process instead ofbeing treated as waste requiring disposal. Starch hydrolysis productionincludes partial or total splitting of the long starch molecules intosmaller fragments by chemical or enzymatic processes, purification,concentration and other unit operations for obtaining the desiredproduct (such as a sweetener product). General descriptions of starchhydrolysis are provided in Kearsley et al., Handbook of StarchHydrolysis Products and Their Derivatives, (1995); Hull, Glucose SyrupsTechnology and Applications, Wiley Blackwell (2010), the disclosures ofwhich are incorporated herein by reference. For example, in Chapter 3,Hull describes glucose syrup manufacture.

In general the commercial processes and associated equipment aredesigned with respect to the type of raw material and final productspecification. Thus, industrially, starch hydrolysis production may varysomewhat depending on the manufacturer and depending on other factors,such as the starch hydrolysate produced and on the dextrose equivalent(or “DE”) value of the product. Starch hydrolysis processes generatewaste materials and it has long been desired to provide alternatives tothe costs associated with treating and disposing waste materials. Inconventional starch hydrolysis, various treatments, including carbontreatments and filtration treatments, are performed to remove undesiredorganic materials, insoluble materials, colors and the like. The carbontreatments typically require forms of powdered carbon and/or granulatedactivated carbon, which generate spent carbon material. In starchhydrolysis production certain filtration treatment can be performedusing diatomaceous earth. In other processes, including certain starchhydrolysis operations as well as various water purification operations,a filtration step may involve a layer of activated carbon over a layerof diatomaceous earth (as a filtration aid), and both can be re-claimedin combination as spent carbon material. In principle, spent carbonmaterial from a carbon treatment can also be mixed with diatomaceousearth from a filtration treatment and used herein provided it capable ofbeing extruded in accordance with the present invention. Although notpreferred, spent carbon can be combined with fresh diatomaceous earthfor the purposes of obtaining a spent carbon material for forming ablend from which the moisture absorbent additive can be prepared. And,in principle, fresh activated carbon can be combined with re-purposeddiatomaceous earth from a filtration system, such as from starchhydrolysis or a brewing process. The present inventions include methodsfor forming the product from any of such materials.

Diatomaceous earth is known as diatomite, is a naturally occurring,soft, siliceous sedimentary rock that is easily crumbled into a finewhite to off-white powder. It can have a particle size ranging from lessthan 1 micrometer to more than 1 millimeter, but typically 10 to 200micrometers. This powder has an abrasive feel, similar to pumice powderand is very light, due to its high porosity. The typical chemicalcomposition of an oven dried diatomaceous earth is 80 to 90% silica,with 2 to 4% alumina (attributed mostly to clay minerals) and 0.5 to 2%iron oxide. Diatomaceous earth consists of fossilized remains ofdiatoms, a type of hard-shelled algae. Diatomaceous earth itself may beused as a primary ingredient in cat litter formulations for liquid andodor absorption and poses no harm to chemical harm to humans or animalsdue to its formation in a freshwater source, but by itself does not havethe carbon materials (activated carbon or powdered carbon) contemplatedby the term spent carbon materials.

In general, the diatomaceous earth component in or combined to form aspent carbon material can be any commercially available diatomaceousearth. Hence, in principle most silica based diatomaceous earths can beutilized. A spent carbon material may include Celatom FW-14 (Celatom) orFW-14 (EP Minerals) brand diatomaceous earth, as an example.

Re-claimed spent carbon materials typically contain significant amountsof moisture. Spent carbon materials from starch hydrolysis and otherfiltration treatments contain significant amounts of moisture. Amoisture content of approximately 25 to 35% is not unexpected.

The density of spent carbon may depend on its moisture content.

By preference, but not as a requirement, the spent carbon material isblended with other materials, particularly a suitable matrix or bindermaterial, which includes a biodegradable material, to ensure the carbonparticles are embedded in and on the surface of an at least partiallypuffed odor-absorbing product prepared in accordance with a methodembodiment of the present invention. The matrix or binder material can,if desired, re-purposed from another process to reduce waste disposalcost, again as a green process, provided it is suitable for extrusionand is suitable for preparing an at least partially puffedodor-absorbing product. Certain materials can promote cohesiveness inthe odor-absorbing product and are also biodegradable. The binder ispreferably such that the extrudate is cuttable. Other ingredients can beadded to the blend to be extruded, such as anti-microbial agents,especially when the matrix or binder material is biodegradable.

The binder or matrix material can be, for example, powdered or granulargrits or flour, which are biodegradable. Flour includes whole flour aswell as de-germinated flour. Flour can include rice flour, corn flour,wheat flour and the like. By preference the flour is de-germinated cornflour or de-germinated ground corn grits. For example, when the matrixor binder material comprises flour (such as de-germinated corn flour orgranulated corn grits), it can, in principle, function in part as acohesiveness agent. Since such substances are biodegradable, ingredientsto reduce the prospects for spoliation and other ingredients can beadded to the blend before or during extrusion.

The composition (blend) for extrusion contains (on a solids basis)sufficient spent carbon (powdered activated carbon) to provideodor-absorbing capability. Depending on the matrix or binder, sometimesreferred to as a substrate, the composition for extrusion can containupwards of 50% spent carbon, although in principle greater amounts arefeasible provided the at least partially odor-absorbing product does notgenerate unacceptable amounts of carbon dust during packaging, shippingand use.

The blend may be subjected to heat and mechanical work in an extruder toobtain a cohesive and at least partially puffed product. The blendcontaining spent carbon material can be extruded under conditions,temperatures and pressures to provide an extruded, low density pelletthat has the ability to absorb undesirable odors. The product is puffed.The product is dried and is generally considered a low moisture product.A puffed product means the extrudate is at least partially expanded,e.g., a partially puffed.

Preferably, the extrusion back pressure should be sufficient enough toobtain a slightly puffing or expansion effect in combination with shearstress on the ingredients and the effect of moisture flashing off theproduct at an atmospheric or ambient temperature. The back pressure canbe in the range of 500-1000 psi, although in principle other pressurescan be employed.

It is preferred that the extrusion be conducted for such time and attemperatures sufficient to remove any unwanted microbiologicalcontaminants in the blend. It is believed that sterilization may beachieved when subjecting a blend for sufficient time to the elevatedtemperature and pressures in the extruder.

It is presently preferred that, aside from any moisture content of thespent carbon blend, the spent carbon blend is extruded under conditionsin which minimal amounts of moisture are added, more preferably in thesubstantial absence of additional moisture, especially when a spentcarbon material has a relatively high initial moisture content, toachieve expansion and loss of moisture consistent with obtaining aproduct that is moisture-absorbing as well as odor-absorbing. Inprinciple, a minimal amount of water may be added during the extrusion.Moisture from the spent carbon blend and/or from any added water isflashed off. The residual moisture in essence may serve as a blowingagent for the blend as it extrudes through the die(s) of an extruder.This promotes production of an at least partially puffed extrudate.Exemplary addition of moisture is described in the Examples.

It should be appreciated that the extruder is not limited to particularsettings or screw configurations. A suitable extruder is a Wenger TX-57brand twin-screw extruder from Wenger. By preference, the extrusionsystem includes pre-conditioning capabilities, temperature settings andmultiple screw configuration options.

In general, an extruder is provided with an extrusion die(s) and acutter(s). The extrusion die(s) is selected so the die imparts a desiredshape and size to the extrudate. For instance, an opening in a die canhave a circular circumference with a suitable diameter. Common dieconfiguration diameters can range from about 1 mm to 5 mm, particularly2 mm to 4 mm in diameter, and more particularly about 2 mm to 3 mmdiameter. The extrudate is cut to a desired size—length by the cutter.The extrudate from the die(s) is cut to the desired size. A pellethaving a circular circumference is obtainable. The discrete pellets canbe processed further as needed.

It will be appreciated that the extrusion conditions are selected sothat an expanded cuttable extrudate is obtained. Preferably theextrudate is cut before drying.

The extrudate is then dried to the desired moisture content. The producthas a moisture content that is sufficiently high to prevent theparticles from being friable, but preferably sufficiently low enoughthat the product has capacity to absorb moisture.

The extruded, low density spent carbon additive can be granular but isnone-the-less preferably at least partially puffed, and thus porous. Theat least partially puffed product has a greater exposed surface areawith activated carbon than a comparably sized solid particle becauseexterior and interior surfaces are exposed due to its expandedstructure. In contrast, in a solid granulated particle each layer issuccessively accreted over a prior layer to form a large granule wherebycarbon particles in successive under layers are buried in the process ofgranulation, and thus the available exposed surface for odor absorption(carbon particles) is undesirably substantially reduced.

By way of exemplification: Fifty pounds of spent carbon containingdiatomaceous earth and powdered activated carbon was obtained fromstarch hydrolysis production (Grain Processing Corporation of Muscatine,Iowa) and was blended with 144 pounds de-germinated ground corn gritsfrom ConAgra, 2 lbs. of citric acid (Tate & Lyle) and 4 lbs. fine gradesalt (Cargill Inc.). The blended material was extruded in a twin screwextruder (Model TX-57 brand twin screw extruder, Wenger) using a feedrate of 180 lb/hr with a cylinder speed of 350 RPM and shaft speed at160 RPM. 3.7 lb/hr steam was forced through cylinder while also feeding4 lb of water/hr. The extruder was provided with a die containing 17, 3mm diameter die holes. The extruder was provided with a cutter havingthin stainless steel blades and the cutter was set so the blades rotatedat 3000 RPM with minimal back pressure. The twin screw extrudercontained five separately heated chambers that were each set to specifictemperatures to control shear and expansion to adhere all ingredients inblend to one another. The blend was extruded through the die and cutwith the cutter to obtain puffed circular pellets sized 3-4 mm andimmediately dried using a belt dryer set at 185° F. (85° C.) and aslightly puffed, low density carbon, odor absorbing granular additivewith minimal moisture content was obtained. The spent carbon used had amoisture content in the range of 20-50%. The extrudate produced had aloose density of around 25 lbs/cu. Ft.

The litter may be provided with a fragrance-imparting material toprovide a pleasant scent. In one aspect, a scent is provided from anatural source, such as but not limited to alfalfa, almond, amber,angelica root, anise, apple, apricot, banana, basil, bay, bay laurel,benzoin, bergamot, bitter orange, black pepper, bois de rose (rosewood),cajeput, cardamom, carrot seed, cedarwood, cedarwood atlas, cinnamon,citronella, citrus, clary sage, clove, cocoa, coconut, coffee,coriander, cranberry, cypress, elemi, eucalyptus globulous, eucalyptus,fennel, frankincense, galbanum geranium, German chamomile, ginger,grapefruit, helichrysum, hyssop, jasmine, juniper berry, lavender,lemon, lemongrass, lily, linden blossom, mango, marjoram, melissa, mint,myrrh, myrtle, neroli, niaouli, nutmeg, orange, oregano, palm, parsley,patchouli, peach, peppermint, petitgrain, pine, pineapple, raspberry,Roman chamomile, rose, rosemary, sandalwood, spearmint, spruce,strawberry, tea, thyme, vanilla, vetiver, violet, yarrow, ylang vlang,and the like. Plant parts that do not provide a scent or have very lowscent but that are visually appealing can also be used. The plant partscan be subjected to a process to reduce the size of the parts to a sizesuitable for addition to an animal litter.

Essential oils or other plant extracts can be used in the littersdescribed herein. Extracts can be physically obtained, such as bypressing or squeezing, or by using solvent, such as oil, organicsolvent, or water, to process plant parts. For example, orange oil canbe obtained from orange peels, and rose oil can be extracted from rosepetals using vegetable or mineral oil. Commercially-available essentialoils can also be used, if desired. By one approach, one or more plantextracts or essential oils can be blended to provide a desired scent.For example, a blend of plant extracts can be provided to give a rose,“earthy,” “spring,” “fresh,” “ocean,” or other desired scent as can bereadily formulated by a skilled person in the art.

In one aspect, the deodorizing agent may include natural or syntheticfragrances. Suitable fragrances include, for example, Modern Lavender,Lavender Fields, Natural Fresh Clean, Baby Fresh Natural, Natural AmberBalsam, Natural Sweet Amber, Natural Fresh Citrus, Natural Fresh Air,and Rose from Fragrance West, Van Nuys, Calif., Baby Fresh, Lilac,Violet, Rose, Jasmine, and Lavender from Bell Flavors & Fragrances,Inc., Northbrook, Ill., Natural Lavender, Rose Geranium, NaturalRosemary Mint, Baby Powder, and Fresh Blossoms Natural from Flavor andFragrance Specialties, Mahwah, N.J., and Lavender, Jasmine, Amber, andFresh Wave from Alpha Aromatics, Fox Chapel, Pa.

In some embodiments, the litters provided herein include colorful plantparts, such as flowers, flower buds, petals, or the like, to providevisually appealing colored particles to the litter. In one aspect, thecolorful plants parts also provide a natural scent to the litter. Inanother aspect, the colorful plant parts are provided in combinationwith a natural based fragrance, such as with a scented oil. For example,brightly colored particles made from dried flowers and petals are oftenweak in scent and the fragrance of the particles can be enhanced byinclusion of a natural or synthetic fragrance.

The litter may include a blend of essential oil formulated to havelavender scent. For example, “Natural Lavender” fragrance Item#114B13 or112E13 made by Flavor and Fragrance Specialties, Mahwah, N.J., can besprayed onto the animal litter at the ratio of 1.6 to 3.5 pounds per tonto provide the litter with a lavender scent.

By another approach, a blend of essential oil formulated to freshblossom scent, like the “Fresh Blossoms Natural” fragrance item#112B17made by Flavor and Fragrance Specialties, Mahwah, N.J., can be sprayedonto the animal litter at the ratio of 1.6 to 3.5 pounds per ton toprovide the litter with a fresh flower blossom scent.

The litter may include dried lavender flowers and flower buds can beadded to the lavender or fresh blossom scented litter at a ratio of 1 to6.3 pounds per ton of litter. The dried lavender flowers and budsprovide a pleasant and sweet scent to the litter while also providingbright colored particles which are appealing to consumers. The flowersprovide the impression of a natural fresh scent even though the scent isprovided primarily from the essential oil.

In another aspect, dried global amaranth flowers and flower petals canbe added to the lavender or fresh blossom scented litter.

By another approach, no scented oils are added to the litters. Instead,dried global amaranth flowers and flower petals are added at a ratio ofabout 0.88 pounds per ton of litter and lavender flowers and buds areadded at a ratio of about 6.3 pounds per ton of litter. The globalamaranth flowers and petals have significantly brighter color than thelavender flowers and provide brightly colored particles that areappealing to consumers but are weak in scent. The dried lavender flowersand buds provide an appealing visual appearance and a pleasant and sweetscent to the litter. The colorful amaranth flowers and scent from thelavender flowers provide consumers with the impression of a natural,fresh scent.

In yet another aspect, dried “forget-me-not” flowers, rose petals,purple clover flowers, global amaranth flowers and flower petals,cornflower, cowslip, St. John's wort flowers, yarrow flowers, or fieldpoppy flowers, are added to the litter at a ratio of about 0.88 poundsto 2 pounds per ton of litter. The dried flowers and petals providebrightly colored particles that are appealing to consumers.

By one approach, the scent of the litter can be changed seasonally. Forexample, the litter can be scented to reflect each of the four seasonsof the year. For example, a coffee scent can be prepared from spentcoffee grounds. A vanilla scent can be provided from vanilla extract. Acoconut scent can be provided from coconut copra pellets. A strawberryor apple scent can be provided by addition of apple or strawberryby-products.

In some cases, the animal litter including plant parts and/or fragranceis packaged under conditions effective to lengthen the shelf life of thescented product. In one aspect, the scented litters can be packaged in aplastic bag with oxygen barrier properties, such as, for example, alaminated polyethylene and polyester or nylon plastic package. Inanother aspect, the packaging is purged with nitrogen gas to reduce theoxygen level inside the package to less than 10 percent v/v, preferablyless than 2 percent v/v. The lower oxygen content would reduce theoxidization of components of the natural fragrance, which was believedto reduce the shelf life of the natural fragrance. Under theseconditions, the shelf life of the scented litter is at least about 20weeks.

The animal litter preferably has a moisture content sufficiently high toprevent the articles of animal litter from becoming friable andsufficiently low to allow additional moisture to be absorbed.Preferably, the moisture content of the inventive animal litter is lessthan about 30% based on the weight of the litter. More preferably, themoisture content ranges from about 3% to about 25%; even morepreferably, the moisture content ranges from about 5% to about 20%; andmost preferably the moisture content is from about 5% to about 15%. Itis contemplated that some of the moisture in the animal litter will bepresent originally in the sorbent materials and/or cohesiveness agent.In some embodiments, the moisture content will be about 12% or less

In exemplary embodiments, the animal has been found effective insuppressing odors of animal waste such as animal urine. Animal urinecontains urea, allantoin, or other compounds which break down to formammonia. The ammonia odor of spent animal litter is often considered tobe objectionable. Animal litters made in accordance with thisapplication will be effective in substantially reducing ammonia odors,and a litter box (housed or exposed) containing such litter will remainsubstantially free from ammonia odors for about 30 hours or more afterthe animal has excreted waste into the litter.

In one form, the animal litter preferably has a density sufficient toallow interparticle binding, yet that will minimize the weight of thelitter. The litter preferably has a bulk density ranging from about400-800 kg/m³. Lighter density may have a tendency to make the littertoo light and result in “tracking” by an animal, such as a cat. Densitypreferably is evaluated after loosely filling a container and measuringthe weight of a specific volume of the litter.

It will be appreciated that the particle size distribution can have aneffect on the functional properties of the animal litter. If there is arelatively high population of very large particles, the litter mayabsorb liquids more slowly and also may be less effective in maskingammonia odor or other undesirable odors of spent animal litter. On theother hand, a relatively high population of small particles or fines canresult in “tracking” and reduced clump strength. In many embodiments,the particle size of the finished litter is such that more than 90% ofthe particles are larger than a U.S. standard #20 mesh screen size whileessentially all of the litter is smaller than a U.S. standard #5 meshscreen size. In some embodiments from 8-15% is larger than a U.S.standard #8 mesh screen size; 55-75% are larger than a U.S. standard #14mesh screen size but smaller than a U.S. standard #8 mesh screen size,where essentially all of the rest is between a U.S. standard #14 meshscreen size and a U.S. standard #20 mesh screen size. In someembodiments finer particles are not present; in other embodiments, finerparticles are present in an amount effective to about 20%; in somecases, up to about 15%; and in some cases, up to about 12%.

Because the animal litter is to be used to absorb animal waste, e.g.,urine, the litter should have an absorption capacity sufficient to allowthe animal litter to so function. The absorption capacity of the litterpreferably is at least about 0.05 ml water per gram of litter, morepreferably ranges from about 0.5 to about 1.5 ml/g, and most preferablyranges from about 0.5 to about 1. ml/g. The absorption capacitiesspecified herein are determined per gram of animal litter, based on theabsorption of deionized water. Preferred absorption capacity rangesbased on the absorption of deionized water are believed to approximatethat of animal urine.

Other properties may be desired of an animal litter. For example, tominimize inconvenience and mess associated with packaging, transporting,and using the litter, the litter preferably generates a minimal amountof dust. In one form, the preferred litters do not generate substantialdust, and ordinarily do not require dust reducing agents (although suchmay be added if desired). Moreover, the preferred litters have asand-like texture that is not fluffy, which is preferred by domesticanimals such as cats.

Another preferred property is clumping efficiency. Clumping efficiencyis the amount of litter required to form a dump with a given volume ofliquid, with lower amounts of required litter corresponding to higherclumping efficiencies. Preferably, to absorb 30 ml animal urine, lessthan about 60 g of litter is required; more preferably, less than about40 g is required.

Other desired properties include biodegradability and tendency to remainclumped over time. Biodegradability is a particularly preferred propertywhen it is desired to dispose of clumps of litter by flushing them intothe toilet. The litter is believed to be at least as biodegradable asother grain-based litters, and thus the litter may be disposed of byflushing, even into a septic system. Moreover, the litter exhibitscontrolled water-absorbing capacity, making it easily flushable down atoilet without excessive expansion. This property can help avoidblockages of drain pipes, e.g., when cat owners flush the soiled litterdown the toilet. Tendency to remain clumped refers to the stability ofthe clump of the soiled litter. A clumping litter should remain clumpedfor at least 24 hours after the clump has formed. In one form, thelitters have an excellent tendency to remain clumped.

A process for preparing an animal litter is also provided. Generally,the process comprises compacting ingredients forming the animal litterinto discrete plural particles of a size suitable for use as a litter.In some embodiments, the particle size is accomplished by reducing alarger mass to the desired size. Preferably, the process includes a stepof compacting or compressing the particles of animal litter intogranules or pellets, which most preferably is accomplished in apelletizing operation. The stabilizer or mold inhibitor, cohesivenessagent, and/or lubricant, when used, can be added at any suitable stage,and preferably are mixed with the other components of the litter in thedesired proportions prior to pelletizing of the grain-based substrate.

When a pellet mill is employed, the moisture content in the pellet millfeed preferably is in the ranges described herein with respect to themoisture content in the finished product, and preferably is 10-14%.Optionally, moisture can be added to the feedstock in the form of liquidwater to bring the feedstock to the desired moisture content. Thetemperature in the pellet mill preferably is brought to about 70-90° C.,e.g., 82° C., using steam. The pellet mill may be operated under anyconditions that impart sufficient work to the feedstock to providepellets. It is believed that the particle size of the startingmaterials, the temperature within the pellet milt and other variablescan affect the properties of the final product. The pellet mill can beoperated with a suitable die (e.g., a 3/32 in. times 5/32 in. die) at apressure and temperature effective to provide pellets. The pelletspreferably are then crumbled in a pellet mill crumbler to providediscrete plural particles having a particle size capable of passingthrough an 8 mesh screen but being retained on a 20 mesh screen, orotherwise as described above. As described herein, lubrication ispreferably provided by adding a virgin germ. In other embodiments,lubrication may be provided by adding another lubricant, such as avegetable oil.

A method for removing animal waste is also provided, which methodgenerally contemplates providing a container containing an animal litterdescribed herein, allowing an animal to excrete waste into thecontainer, whereby moisture from the waste causes the animal litter toagglomerate into at least one clump; and removing the clump of litterfrom the container and preferably any solid waste so as to remove theanimal waste. By “container” is meant to include any enclosed orpartially enclosed area, such as a litter box, a cage, a stall, a pen(such as a poultry coop), or the like. The method for the removal ofanimal waste is contemplated to be useful for all animals capable ofexcreting waste on land, such as cats, dogs, mice, birds, gerbils,reptiles, and other animals, and finds particular applicability inconnection with removal of waste from domestic house cats. The methodfor the removal of animal waste also may be useful for the removal ofwaste generated by farm animals such as chickens, livestock, or thelike.

The following examples further illustrate the invention, but should notbe construed as in any way limiting the scope of the invention.

EXAMPLES Example 1

An animal litter was prepared by mixing the following ingredients andpelletizing using a pellet with a 3/16 inch diameter holes and 2 inchvariable thickness die (1⅝ inch and 2 inch thickness) at a temperatureof around 180° F.

Ingredient % Total Weight Fine Ground Corn Cob 61.9 Corn Starch (B20F)*30 Ground Virgin Corn Germ 4 Salt 3 Citric Acid 1 Potassium Sorbate 0.1*Corn starch B20F is available from Grain Processing Corporation ofMuscatine, Iowa.

The materials were mixed together and then pelletized in a pellet millwith a 5/32 inch die of a 3/16 inch by 2 inch die (1⅝ inch and 2 inchthickness). The pellet mill was operated at a temperature of about165-170° F. The product was dried to a moisture content below 12%. Thefinal product was then crumbled to reduce the size of the particles. Thefinished product had a size distribution as shown in Table 2 below:

TABLE 2 Particle size distribution. % Over % Over % Over % Over % Over %Over #8 #14 #20 #30 #40 #80 Sieve Sieve sieve Sieve Sieve Sieve % in pan8-15 55-75 10-20 <6 <3 <2 <1

The litter prepared according to Example 1 was suitable for use as ananimal litter.

Example 2

To the litter formulation of Example 1 is added a puffed extrudedodor-absorbing material prepared in accordance with U.S. ApplicationSer. No. 61/600,966. The odor-absorbing material is added in the amountof 2% by weight. The litter is prepared by mixing the ingredients usinga small plant size pellet mill with a 3/16 inch diameter holes and a 2inch variable thickness die (1⅝ inch and 2 inch thickness) at atemperature of around 180° F.

Example 3

An animal litter was prepared by mixing the following ingredients andpelletizing using a pellet mill with 5/36 inch diameter holes with a 2inch variable thickness die at a temperature between 160-175° F.

Ingredient wt % Ground Citrus Orange peel/pulp 20 Pellets ( 1/16″screen) Ground Corn Cobs (through 20 1/16″ screen) DCM-120* 41.9 Ground75:25 blend of DCM-120 15 and virgin germ Citric acid 1 Salt 2 PotassiumSorbate 0.1 *DCM-120 is defatted corn germ meal.

The litter was found to be a satisfactory cat litter and to have a clumpweight of 53 grams, when evaluated by the methods disclosed inWO03/04513482, a PCT publication of Lin Wang and Thomas A. Wiesner, andassigned to Grain Processing Corporation of Muscatine, Iowa.

Example 4

An animal litter was prepared by mixing the following ingredients andpelletizing using a pellet mill with a 3/16 inch×2 inch die size(effective thickness 1⅝ inch and 2 inch) at a temperature of around 180°F.

Ingredient wt % Fine Ground Corn Cob 59 Corn Starch (B20F) 30 Groundvirgin corn germ 7.9 Salt 2 Citric acid 1 Potassium Sorbate 0.1

The litter was deemed suitable for use as an animal litter.

Example 5

An animal litter was prepared by mixing the following ingredients andpelletizing using a pellet mill with 5/32 inch diameter holes and a 2inch VR+NVR (variable relief non variable relief) die at a temperaturebetween 160-175° F.

Ingredient wt % Fine Ground corn cob 53 Fine Ground Malt Sprouts 20.00Corn Starch 20.00 Virgin Corn germ 3.00 Salt 3.00 Citric acid 1.00

Comparative Example 1

In the same manner as in Example 5, an animal litter was prepared,except that the ingredients were pelletized using a pellet mill with3/16 inch diameter holes and a 1 inch thickness.

Ingredient wt % Fine Ground corn cob 53 Fine Ground Malt Sprouts 20.00Corn Starch 20.00 Virgin Corn germ 3.00 Salt 3.00 Citric acid 1.00

Example 6

The following ingredients ere blended and pelletized using a pelletizerwith a 5/32 inch×½ inch die.

Ingredient wt % Fine ground corn cobs 43 Fine Ground Malt Sprouts 25.00Corn Starch 25.00 Virgin Corn germ 3.00 Salt 3.00 Citric acid 1.00

Comparative Example 2

In the same manner as in Example 6, the following ingredients werepelletized, except that the die size was 3/1.6 inch×1 inch.

Ingredient wt % Fine ground corn cobs 43 Fine Ground Malt Sprouts 25.00Corn Starch 25.00 Virgin Corn germ 3.00 Salt 3.00 Citric acid 1.00

The following results were obtained.

Example Clump Weight Example 5 57.9 Comparative Example 1 Failed Example6 57.7 Comparative Example 2 Failed

While it is not intended to limit the invention of a particular theoryof operation, it is believed that, in light of the different diegeometry of the comparative examples vs. Examples 5 and 6, the animallitter product was “cooked” via pelletizing more than desired, thusleading to a product that did not clump satisfactorily.

Example 7

An animal litter was prepared by mixing the following ingredients andpelletizing using a small pilot plant size pellet mill with 5/32diameter holes with a ½″ thickness die at a temperature between 155-175°F.

Ingredient wt % Ground Citrus Peel Pellets 20 Fine Ground Corn Cobs 20Ground Corn 56.85 Citric acid 1 Salt 2 Potassium Sorbate 0.15 MoistureAs-is

The resulting product was a satisfactory animal litter. When tested, thelitter had a clump weight of 60.8 grams and a clump strength of 133.

Example 8

An animal litter was prepared by mixing the following ingredients andpelletizing using a small pilot plant size pellet mill as described inthe previous example.

Ingredient wt % Fine Ground Corn Cobs 29.85 Ground Corn 67 Citric acid 1Salt 2 Potassium Sorbate 0.15 Moisture As-is

The litter thus prepared had a clump weight of 63.8 grams.

Example 9

An animal litter was prepared using the processing conditions asdescribed in the previous two examples and using the followingingredients.

Ingredient wt % Fine Ground Corn Cobs 20.00 Ground Corn 76.85 Citricacid 1 Salt 2 Potassium Sorbate 0.15 Moisture As-is

The product had a clump weight of 67.3 grams and a clump strength of 224grams.

Examples 10-14

Animal litters were prepared in accordance with the following examples.Each litter was prepared in a pelletizer.

Example 10 Ingredient ratio Ground Corn cobs (through 30 1/16″ screen)Starch 12 Ground 75:25 blend of DCM-120 15 and “virgin” germ DCM120 40Citric acid 1 Salt 2 Potassium Sorbate 0.15 Moisture As-is 100.15

Example 11 Ingredient ratio Ground Corn cobs (through 25 1/16″ screen)Starch 12 Ground 75:25 blend of DCM-120 15 and “virgin” germ DCM120 45Citric acid 1 Salt 2 Potassium Sorbate 0.15 Moisture As-is 100.15

Example 12 Ingredient ratio Ground Corn cobs (through 20 1/16″ screen)Starch 12 Ground 75:25 blend of DCM-120 15 and “virgin” germ DCM120 50Citric acid 1 Salt 2 Potassium Sorbate 0.15 Moisture As-is 100.15

Example 13 Ingredient ratio Ground Corn cobs (through 40 1/16″ screen)Starch 12 Ground 75:25 blend of DCM-120 15 and “virgin” germ DCM120 30Citric acid 1 Salt 2 Potassium Sorbate 0.15 Moisture As-is 100.15

Example 14 Ingredient ratio Ground Citrus Orange peel/pulp 20 Pellets (1/16″ screen) Ground Corn cobs (through 20 1/16″ screen) Starch 12DCM-120 30 Ground 75:25 blend of DCM-120 15 and “virgin” germ Citricacid 1 Salt 2 Potassium Sorbate 0.15 Moisture As-is 100.15

Each example was prepared generally in accordance with the foregoingteachings by pelletizing the ingredients in the pellet mill. The litterswere evaluated and the following results were observed.

Clump weight Ammonia- Example (5-min) gram masking Comments Example 1059 Slight slightly long, but ammonia strong clump Example 11 58.8 Good,none to slightly long, but very little strong clump ammonia Example 1260.2 No ammonia Firm, solid clump Example 13 54.4 Slight Good clump,ammonia slightly long, but strong Example 14 56.6 Good, none to Goodclump, very little slightly long, but ammonia strong

Example 15

An animal litter product was prepared by mixing the followingingredients and pelletizing using a small pilot plant size pellet millwith a ⅛ inch diameter holes with a ½ inch thickness small die at atemperature between 155-475° F.

Ingredient ratio Ground Citrus Orange peel/pulp 15 Pellets ( 1/16″screen) Ground Corn cobs (through 30 1/16″ screen) DCM-120 37 Ground75:25 blend of DCM-120 15 and “virgin” germ Citric acid 1 Salt 2Potassium Sorbate 0.15 Moisture As-is Total 100.15

Example 16

An animal litter was prepared in accordance with the same method as theprevious example using the following ingredients.

Ingredient ratio Ground Citrus Orange peel/pulp 20 Pellets ( 1/16″screen) Ground Corn cobs (through 25 1/16″ screen) DCM-120 37 Ground75:25 blend of DCM-120 15 and “virgin” germ Citric acid 1 Salt 2Potassium Sorbate 0.15 Moisture As-is Total 100.15

Example 17

An animal litter product was prepared by mixing the followingingredients and pelletizing using a small pilot plant size pellet millwith a 3/32 inch diameter holes with a ⅝ inch thickness small die of atemperature between 155-175° F.

Ingredient ratio Ground Citrus Orange peel/pulp 15 Pellets ( 1/16″screen) Ground Corn cobs (through 30 1/16″ screen) DCM-120 37 Ground75:25 blend of DCM-120 15 and “virgin” germ Citric acid 1 Salt 2Potassium Sorbate 0.15 Moisture As-is Total 100.15

Example 18

An animal litter product was prepared by mixing the followingingredients and pelletizing using a small pilot plant size pellet millwith a ⅛ inch diameter hole with ½ inch thickness die at a temperaturebetween 155-175° F.

Ingredient ratio Ground Citrus Orange peel/pulp 20 Pellets ( 1/16″screen) Ground Corn cobs (through 20 1/16″ screen) DCM-120 42 Ground75:25 blend of DCM-120 15 and “virgin” germ Citric acid 1 Salt 2Potassium Sorbate 0.15 Moisture As-is

The litters of Examples 1548 were evaluated and the following resultswere observed:

Clump weight Ammonia- Example (5-min) gram masking Comments Example 1555 OK, Slight ammonia Example 16 56.3 Excellent, no ammonia Example 1757.6 Excellent, no ammonia Example 18 55.4 Excellent Nice firm spongeclumps

Example 19

An animal litter product was prepared by mixing the followingingredients and pelletizing using a small pilot plant size pellet millwith 3/16 inch diameter holes and a 2 inch variable thickness die (1⅝inch and 2 inch thicknesses) at a temperature of around 180° F.

Ingredient wt % Pine sawdust 20-mesh 25.00 Fine Ground Corn Cob 35.00 (1/16 screen) Corn Starch (B20F) 32.00 Ground Virgin Corn Germ 4.90 Salt2.00 Citric Acid 1.00 Potassium Sorbate 0.10

The litter of Example 19 exhibited an excellent clumping property, withan average clump weight of 52.7 grams, excellent ammonia masking, andtight solid clumps with satisfactory clump strength.

Example 20

An animal litter product was prepared by mixing the followingingredients and pelletizing using a small pilot plant size pellet millwith 3/16 inch diameter holes and a 2 inch variable thickness die (1⅝inch and 2 inch thicknesses) at a temperature of around 180° F.

Ingredient wt % Pine sawdust 20-mesh 20.00% Fine Ground Corn Cob 42.00%( 1/16 screen) Corn Starch (B20F) 30.00% Ground Virgin Corn Germ 3.90%Salt 3.00% Citric Acid 1.00% Potassium Sorbate 0.10%

The litter exhibited an excellent clumping property, with an averageclump weight of 52.5 grams, excellent ammonia masking, and tight solidclumps with satisfactory clump strength.

Example 21

An animal litter product was prepared by mixing the followingingredients and pelletizing using a pellet mill with 3/16 inch diameterholes and a 2 inch variable thickness die (1⅝ inch and 2 inchthicknesses) at a temperature of around 180° F.

Ingredient wt % Fine Ground Corn Cob 64.2% Unmodified Corn Starch 27.0%Ground virgin corn germ 5.0% Salt 3.0% Citric acid 0.7% PotassiumSorbate 0.1%

The product was pelletized and crumbled to the following particle sizedistribution.

% Over % Over % Over % Over % Over #8 #14 #20 #30 #40 % Over # SieveSieve sieve Sieve Sieve 80 Sieve % in pan 8-15 55-75 10-20 <6 <3 <2 <1

This product had excellent suitability as an animal litter. Thefollowing properties were evaluated and determined.

Clump Loose Packed Weigh (g) Clump Ammonia Bulk Bulk Average ClumpingStrength Masking Density Density 59.6 Excellent Solid Excellent 32.735.2

It is thus seen that animal litters may be prepared in accordance withthe foregoing teachings.

All percentages stated herein other than moisture percentages arespecified on a dry solids basis unless otherwise indicated.

All references and previous applications cited are hereby incorporatedby reference in their entireties.

Uses of singular terms such as “a,” “an,” are intended to cover both thesingular and the plural, unless otherwise indicated herein or clearlycontradicted by context. The terms “comprising,” “having,” “including,”and “containing” are to be construed as open-ended terms. Anydescription of certain embodiments as “preferred” embodiments, and otherrecitation of embodiments, features, or ranges as being preferred, orsuggestion that such are preferred, is not deemed to be limiting. Theinvention is deemed to encompass embodiments that are presently deemedto be less preferred and that may be described herein as such. Allmethods described herein can be performed in any suitable order unlessotherwise indicated herein or otherwise clearly contradicted by context.The use of any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended to illuminate the invention and does notpose a limitation on the scope of the invention. Any statement herein asto the nature or benefits of the invention or of the preferredembodiments is not intended to be limiting. This invention includes allmodifications and equivalents of the subject matter recited herein aspermitted by applicable law. Moreover, any combination of theabove-described elements in all possible variations thereof isencompassed by the invention unless otherwise indicated herein orotherwise clearly contradicted by context. The description herein of anyreference or patent, even if identified as “prior,” is not intended toconstitute a concession that such reference or patent is available asprior art against the present invention. No unclaimed language should bedeemed to limit the invention in scope. Any statements or suggestionsherein that certain features constitute a component of the claimedinvention are not intended to be limiting unless reflected in theappended claims. Neither the marking of the patent number on any productnor the identification of the patent number in connection with anyservice should be deemed a representation that all embodiments describedherein are incorporated into such product or service.

The invention claimed is:
 1. An animal litter comprising: a sorbentcomprising at least about 35 weight % ground corn cob; a lubricant; anda cohesiveness agent, the animal litter being in the form of discreteplural particles which tend to agglomerate when wetted, the cohesivenessagent being present in an amount effective to enhance the intraparticlecohesion of the particles, wherein the ground corn cob contributes tothe agglomeration of the litter and is in the form of a finely groundcorn cob configured to pass through a 1/16 inch screen, and wherein nomore than about 5% of the ground corn cob is larger than U.S. standard#30 mesh screen size, at least 50% of the ground corn cob is smallerthan U.S. standard #40 mesh screen size, and at least 20% of the groundcorn cob is smaller than U.S. standard #80 mesh screen size.
 2. Theanimal litter of claim 1 wherein the lubricant is selected from thegroup consisting of corn germ, virgin corn germ, fats, oils and mixturesthereof.
 3. The animal litter of claim 1 wherein the cohesiveness agentis corn starch.
 4. The animal litter of claim 1 further comprising amold inhibitor selected from the group consisting of citric acid,potassium sorbate and mixtures thereof.
 5. The animal litter of claim 1further comprising at least about 10 weight % pine sawdust.
 6. A processfor preparing an animal litter, the method comprising: providing amixture of a sorbent comprising at least about 35 weight % ground corncob, a lubricant and a cohesiveness agent; and compacting the mixture ofinto discrete plural compacted particles which tend to agglomerate whenwetted, wherein the ground corn cob contributes to the agglomeration ofthe litter and is in the form of a finely ground corn cob configured topass through a 1/16 inch screen, and wherein no more than about 5% ofthe ground corn cob is larger than U.S. standard #30 mesh screen size,at least 50% of the ground corn cob is smaller than U.S. standard #40mesh screen size, and at least 20% of the ground corn cob is smallerthan U.S. standard #80 mesh screen size.
 7. The process of claim 6wherein the lubricant is selected from the group consisting of corngerm, virgin corn germ, fats, oils and mixtures thereof.
 8. The processof claim 6 wherein the cohesiveness agent is corn starch.
 9. The processof claim 6 wherein the mixture further comprises a mold inhibitorselected from the group consisting of citric acid, potassium sorbate andmixtures thereof.
 10. The process of claim 6 wherein the mixture furthercomprises at least about 10 weight % pine sawdust.
 11. The animal litterof claim 1, further including at least 2% of a puffed odor-absorbingcarbon based material.
 12. A process according to claim 6, said mixturefurther including at least 2% of a puffed odor-absorbing carbon basedmaterial.